A new T. rex of
the leech world has been named — one with ferociously large teeth, but only a
tiny body and just one jaw.

This new leech species, Tyrannobdella
rex, which means "tyrant leech king," was first discovered three
years ago in the nostril of a 9-year-old girl by Peruvian physician Renzo
Arauco-Brown. The child frequently bathed in lakes, rivers and streams in the
Amazonian part of Peru and had felt a sliding sensation in the back of her
nose.

Two earlier cases from 1997 were re-discovered from
different clinics in the western Amazon.

"We named it Tyrannobdella
rex because of its enormous teeth," said researcher Mark Siddall,
curator in the division of invertebrate zoology at the American Museum of
Natural History in New York.

Although its teeth only reach up to 130 microns high — a
little more than the width of a human hair — "that's at least five times
as high as that of other leeches," Siddall said. "And every one of
the people who were found with these in the clinical cases had a frontal
headache. Their teeth are big, and these things hurt."

Still, its other physical traits belie its majestic name.
The leech is less than two inches long (5 centimeters), and it possesses
extremely small
genitalia.

"The width of the adult leech is about 1 centimeter, or
about the width of my pinkie, while the genitalia are about one-tenth to
one-fifth the width of a millimeter, or 100 to 200 microns," Siddall
explained. "The diameter of a blood cell is only about seven
microns."

Unlike any other known leech, this new species has just one
jaw. "It uses it like a saw," Siddall told LiveScience. "It
doesn't need a huge wound, because it has incredible suction power to get
blood."

World famous, with
ancient history

Unlike many leeches, which
latch onto bodies from the outside, this new T. rex has the unnerving tendency to seek out the insides of a
victim.

Genetic analysis suggests this leech is closely related to a
Mexican bloodsucker, Pintobdella
chiapasensis, which infests the mouths of tapirs and cows, as well as
others in India and Taiwan, such as Dinobdella
ferox, a terrible, ferocious leech well-known for feeding on mucus
membranes and getting into various human orifices.

All of these species, and others from Mexico, Africa and the
Middle East, make up the family Praobdellidae, a group of leeches that seems to
attack mammalian body openings. Until now, such behavior has been regarded only
as a loathsome oddity instead of a unifying character, since there had not been
any data suggesting a close relationship for such geographically disparate
species.

The fact that these leeches share family bonds while living
distant from one another suggests their common ancestor must have lived when
the continents were all pressed together into a single landmass before the
supercontinent of Pangaea broke up, the researchers say.

"The earliest species in this family of these leeches
no-doubt shared an environment with dinosaurs about 200 million years ago when
some ancestor of our T. rex may have
been up that other T. rex's
nose," Siddall said.

The regular host of this new T. rex remains unknown.

"We think the leech could feed on aquatic mammals, from
their noses and mouths for example, where they could stay for weeks at a
time," said researcher Anna Phillips, a graduate student affiliated with
the American Museum of Natural History.

Other leeches, other
T. rexes

Besides this new leech, a number of other species share the
abbreviated name T. rex — in addition
to the legendary
carnivorous dinosaur, an ant living in Malaysia, a mole rat found only on
Mt. Kenya, an extinct snail and extinct scarab beetle also bear this formidable
sobriquet.

However, this new T.
rex is not enough for the researchers. There are 600 to 700 species of
leeches that science has described so far, but Siddall and his colleagues
suspect there could be as many as 10,000 species throughout the world.

"Last week we were up to our necks in water in Peru
trying to find more," Siddall said.

The scientists detailed their findings online April 14 in
the journal PLoS ONE.

Editor's Note: The story has been corrected to state that the width of the adult leech is about 1 centimeter, not 1 millimeter.

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Author Bio

Charles Q. Choi

Charles Q. Choi is a contributing writer for Live Science and Space.com. He covers all things human origins and astronomy as well as physics, animals and general science topics. Charles has a Master of Arts degree from the University of Missouri-Columbia, School of Journalism and a Bachelor of Arts degree from the University of South Florida. Charles has visited every continent on Earth, drinking rancid yak butter tea in Lhasa, snorkeling with sea lions in the Galapagos and even climbing an iceberg in Antarctica.